This invention is directed to an electronic stereoscopic viewing device which utilizes an electronic signal to generate parallactically displaced first and second views of an image. The first and second views of the image are generated on a display device and are conducted to the left and right eye of an observer whereby the observer perceives the image three dimensionally.
The stereoscope was invented in the nineteenth century based on Sir Charles Wheatstone's theory of binocular vision. With the advent of photography, the stereoscope became a popular parlor amusement device in the late eighteen hundreds and early nineteen hundreds. Several decades ago, with the advent of color transparencies, a device marketed under the name VIEWMASTER.TM. was introduced and remains popular even to this day.
The common stereoscopic viewing devices are based upon independently presenting to the left and right eyes views of scenes which are equivalent to those views as actually seen by the left and right eyes as a human views the scene. Because the left and right eyes of the human are spaced apart a small distance, each eye perceives the scene in a slightly different manner. There is a parallactic shift of the scene as viewed by the left and right eye because of the angle at which each of the eyes view a particular scene.
Additionally, because the left and right eyes are viewing the scene at different angles with respect to the lighting of the scene, there are slight differences in shades and hues perceivable by the separate left and right eyes.
The stereoscope and other like instruments present to the separate left and right eyes individual views which differ with regard to the parallactic displacement of the views presented for the object in the scene which is displayed. The photographs or transparencies utilized by these devices can be produced by taking a first photograph at one position and then shifting the camera a distance corresponding to the distance between the left and right eye and taking a second photograph. This method has disadvantages because of the time period involved in moving the camera and the actual physical movement of the camera between the taking of the two photographs. To overcome these disadvantages, a single camera having two lenses or a single camera having a single lens and a system of mirrors which directs two light beams through the single lens can be used to simultaneously produce left and right images on a strip of film.
The above described systems result in photographs or transparencies which are static in nature, and while they have a three dimensional effect, they do not convey any motion within the scenes depicted.
With the invention of practical polarizing material during the last half century, it has become possible to develop three dimensional motion pictures. For the three dimensional motion picture, separate left eye and right eye views are directed to the observer from a screen with each of these views being carried by light which is polarized along axes which are rotated differently from each other. The viewer utilizes a set of glasses having polarizing filters with the filter for one eye aligned with the axes of polarization of one of the views and the filter of the other eye aligned with the axis of polarization of the other view. The filters in front of the eyes allow transmission of only that light which is polarized with respect to the axis of the filter of the particular eye and blocks the light which is polarized with respect to the axis of the filter of the other eye. As such, each eye only receives one of the polarized views. Upon receipt of separate left and right eye views through the filtered glasses, the separate views are transmitted by the eyes to the brain for reconstruction of a three dimensional image by the brain.
The stereoscope, VIEWMASTER.TM. and three dimensional motion pictures all require, however, that an existing scene be present or be physically recreated such that the same can be photographed in order to represent the same scene in a three dimensional manner to an observer. These devices thus are limited to reproducing actual scenes, or if directed toward animated scenes, each individual frame of the animated scene must be set up and photographed.
With the miniaturization of electronics in the last two decades, the video arcade game and smaller hand held versions of the same have become possible. The current popularity of these devices is phenomenal. It is presently possible to hook up certain of these devices to home TV sets for display of the games generated by the device on the television set for home use. The currently known arcade and/or video devices, however, are two dimensional and while the amusement and interest associated with the same is exceedingly high, they lack a feeling of being visually a part of the game because their visual projection systems do not correspond to the reality of actual vision or to the three dimensional effects available in the stereoscopic or other three dimensional viewing devices.
Stereoscopic and other three dimensional devices lack the skill and interest which is achieved in the game type video arcade electronic devices and in turn the game type video arcade electronic devices lack the reality of stereoscopic perception available with the stereoscope and other 3D type devices. In order to integrate these seemingly two mutually exclusive aspects, i.e., the game playing ability of the electronic devices and the three dimensional imagery of the stereoscopic devices, it has been suggested to project at a frequency higher than that discernible by the human, alternate parallactic left and right images displayed in associated with the electronic game. This requires the production of strobe-like pulses of these images at a frequency greater than that which can be recognized by the human brain. However, since both the left and right eye of the human observer are viewing both of the parallactically displaced images, the stereoscopic effect achievable by this method is not the same as when the left and right eye actually receive individual parallactic left and right images which are isolated from each other. Furthermore, the relaxation time of the display screen on which these images are generated must be sufficiently short such that the images depicting the right parallax are time differentiated from those depicting the left parallax image.